Simulation study on the active layer thickness and the interface of a-IGZO-TFT with double active layers

doi:10.1007/s12200-014-0451-1

Front. Optoelectron.

2015, Vol. 8

Issue (4) : 445-450 https://doi.org/10.1007/s12200-014-0451-1

RESEARCH ARTICLE

Simulation study on the active layer thickness and the interface of a-IGZO-TFT with double active layers

Xiaoyue LI,Sheng YIN(

),Dong XU

School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China

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Abstract

In this paper, ATLAS 2D device simulator of SILVACO was used for device simulation of inverted-staggered thin film transistor using amorphous indium gallium zinc oxide as active layer (a-IGZO-TFT) with double active layers, based on the density of states (DOS) model of amorphous material. The change of device performance induced by the thickness variation of each active layer was studied, and the interface between double active layers was analyzed. The best performance was found when the interface was near the edge of the channel, by optimizing the thickness of each active layers, the high performance device of threshold voltage (V_th) = −0.89 V, sub-threshold swing (SS)= 0.27, on/off current ratio (I_ON/I_OFF) = 6.98 × 10¹⁴ was obtained.

Keywords amorphous indium gallium zinc oxide (a-IGZO) double active layers interface density of states (DOS) ATLAS

Corresponding Author(s): Sheng YIN

Just Accepted Date: 26 September 2014 Online First Date: 17 November 2014 Issue Date: 24 November 2015

Cite this article:

Xiaoyue LI,Sheng YIN,Dong XU. Simulation study on the active layer thickness and the interface of a-IGZO-TFT with double active layers[J]. Front. Optoelectron., 2015, 8(4): 445-450.

URL:

https://academic.hep.com.cn/foe/EN/10.1007/s12200-014-0451-1
https://academic.hep.com.cn/foe/EN/Y2015/V8/I4/445

Fig.1

Proposed density of states (DOS) model for a-IGZO. E_C and E_V are conduction and valence band edge energies, respectively. Solid curves within the bandgap represent the exponentially distributed band-tail states (g_ta, g_td), while the dash curve near the conduction band edge represents the Gaussian-distributed donor-like oxygen vacancy (OV) states (g_gd)

Fig.2

Schematic of the TFT structure we adopt in this paper

Fig.3

Transfer characteristic curves of IGZO-TFT with different x (DL and SL represent double layers and single layer, respectively)

Fig.4

Carrier distribution of carriers when −5 V gate voltage is applied

Fig.5

Carrier distribution of carriers when 20 V gate voltage is applied

Tab.1

Key simulation parameters of a-IGZO (based on Ref. [8])

Tab.2

Electrical properties of each a-IGZO TFT with different x

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